Stream Order

Feature Description

Rivers in a watershed are divided into main streams and tributaries. In hydrology, river classification is based on factors such as flow volume and morphology. Hydrological analysis can infer specific characteristics of rivers based on their stream order classifications.

The Stream Order function classifies river networks. Using raster stream data and flow direction raster, this tool assigns hierarchical classifications where higher numerical values indicate higher stream orders. SuperMap currently provides two stream ordering methods: Strahler and Shreve.

  • Strahler Method
    The Strahler method was proposed by Strahler in 1957. Its classification rules are defined as:

    • Streams originating directly from sources are classified as 1st order.
    • The confluence of two streams with equal order results in a stream of order+1.
    • The confluence of streams with different orders maintains the higher original order.

    The Strahler method is the most common stream ordering approach. However, since it only increases order when equal-order streams meet, this method preserves only the highest-order connecting channels without considering all network connections.

  • Shreve Method
    The Shreve method was proposed by Shreve in 1966. Its classification rules are defined as:

    • Streams originating from sources are 1st order.
    • The order of a confluence equals the sum of its two tributaries' orders. (e.g., two 1st-order streams form a 2nd-order stream; a 2nd-order and 3rd-order stream form a 5th-order stream.)

    The Shreve method accounts for all connecting channels in the network, where stream magnitudes effectively represent the total number of upstream connections.

Parameter Description

Parameter Default Description Type
Stream Raster Data   Specifies the datasource and dataset containing raster stream data. DatasetGrid
Direction Raster Data   Specifies the datasource and dataset containing flow direction data (generated by Flow Direction tool). DatasetGrid
Stream Order Method STRAHLER Stream ordering method: STRAHLER or SHREVE. StreamOrderType
Target Datasource   Designated datasource for storing result datasets. Datasource
Result Dataset Name   Specifies the name of the output dataset. String

Output

Parameter Description Type
Stream Order Raster Output raster dataset containing stream order classifications. DatasetGrid